[musicale]

Some hardware and software instruments can easily switch from modern A440 to A400 or any desired A frequency, and from equal temperament to various other temperaments - even dynamic tuning. They are really fun to play, particularly the dynamic tunings where you can get highly in-tune chords and scales in any key. Vocal ensembles can also dynamically adjust their tuning, producing amazing overtones. I imagine string and brass ensembles can as well.

Some (non equal-tempered) keyboard instruments have split sharp/flat keys so you can play more in tune in certain keys/scales.

Being able to distinguish these all of these tunings accurately and switch between them as needed seems like it would be a nice skill to have.

[tkgally]

That sounds great. I would like to try playing a keyboard with dynamic tuning sometime.

I should have mentioned that I was a teenager in the early 1970s, and the only pianos I had access to then had strings and could not be retuned on the fly. In retrospect, I came to feel sorry for my teacher, as being conditioned to the arbitrary standard of A=440 prevented her from enjoying playing music on many of the pianos she would have happened to come across.